Settings of Outlook 2013

Dear Users,

i have some questions about outlook if you could answer me it would be so nice of you,

my company website is www.tora.ir and we have made some email addresses,my question is this

when i install outlook on a computer

......!what should i choose between IMAP and POP3

......!what is difference between these two

.....!what should i choose incoming mail server (pop.tora.ir) or (mail.tora.ir)

.....!what should i choose outgoing mail server (smtp.tora.ir) or (mail.tora.ir)

.....!is it possible i set one email address on outlook and the same email address

      again can i set on outlook on another computer.

last part of my question the default port does not works for example if the incoming port is 113 and

outgoing port is 25 it does not works. but if i chage these port and incoming is 110 and outgoing is 587

then it works without any problem. i want to know where these ports effects...on myhosting server or

on my local computer.simply my question is this that why these ports have different numbers ...

Thanks in advance

Tahir Mehmood